1. Technical Field
The present invention relates to a device for invading body canals non-destructively and with a minimum of trauma. More particularly, the invention relates to a device, such as a feeding tube, having one or more removable external projections for dynamic advancement of the distal end of the device to the desired body site.
2. Background Information
Medical devices intended for non-destructive invasion of body canals have typically been provided with a low friction external surface. The low friction surface has a slippery texture to facilitate ingress of the device into the body canal for carrying out a medical procedure, and egress of the device from the body canal following termination of the procedure. Once inserted, such low friction devices were generally suitable for their intended use. However, the devices were often difficult to deliver and properly position at the desired site. In addition, insertion required a good deal of physician time and effort to insure adequate placement.
Recently, as set forth in U.S. Pat. Nos. 6,589,213 and 6,767,339, incorporated by reference herein, it was found that the ingress of the medical device or other instrumentation into a desired body site could be facilitated by providing a structure on the external surface of the device having a bi-directional coefficient of friction with respect to the tissue within the body cavity or canal that is engaged by the device during ingress. As disclosed in the incorporated-by-reference patents, the surface structure could be positioned along the device in a manner such that naturally occurring dynamic functions of the body, such as peristaltic contractions, could be used to grasp the surface structure of the device upon insertion, and carry the device toward the desired work site.
Devices such as those disclosed in the incorporated-by-reference patents have been successfully used, among others, as tubes for delivering feeding materials, drugs, contrast materials or saline, to a target site, within the body of the patient. One primary use of such devices is as jejunal feeding tubes (“J-tubes”) for delivering nutritional products through the esophagus, and thereafter through the stomach or small intestine for delivery to the jejunum. Unlike conventional gastrostomy tubes (“G-tubes”) that are utilized for delivery of nutritional products into the stomach, J-tubes bypass the stomach, and deposit the nutritional products directly into the jejunum (the middle section of the small intestine). Delivery of nutritional products to the jejunum is often preferred to delivery into the stomach, as it decreases the risk of adverse conditions such as gastric reflux and aspiration. In addition, in many cases, delivery directly into the jejunum provides better success in reaching patient nutritional targets, and does so at a more rapid rate than may be achieved with a conventional G-tube.
The device disclosed in the '339 patent employed a series of cilia-like flaps positioned along the external surface of the device. The flaps were positioned in a manner such that the surface could be grasped by the peristaltic contractions, and the distal end of the device propelled toward the target site. Self-advancing tubes, such as those described in the '339 patent, are available commercially from Cook Incorporated, of Bloomington, Ind., and are sold under the trademark TIGER TUBE®. Such tubes have been well received in the medical community, and have been found to achieve a high success rate in post pyloric placement of the feeding tube.
Once successful placement is attained with the self-advancing tubes, there is little or no benefit to maintaining the surface structure, such as the flaps of the '339 patent, on the exterior of the tube. Although the flaps are generally flexible, the presence of such flaps is unnecessary when the tube is withdrawn, and the additional diameter occupied by the flaps may impose an impediment to withdrawal. It would be desirable to provide a device having surface structure suitable for enhancing advancement to the target site by peristaltic contraction, and in which the surface structure is removable following successful placement of the device.